SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d12ad12b1894ae1e61ffd4d5ac568112cb04d770cabed01a580c6b73d03ecbd' 
  AND token = 'ModCsoOHclQKKKU5azGpqX8DPOJupoA6QnOZCtLLU/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}